Transformer.



PATENTED MAY 5, 1903.

2 sums-sum 1.

F A Y W W o M d T. J. JOHNSTON. TRANSFORMER.

APPLICATION FILED Nov. 1, 1902.

N0 MODEL.

No. 726,936- PATBNTED MAY 5, 1903. T. J. JOHNSTON.

TRANSFORMER.

APPLICATION FILED NOV. 1; 1902.

F0 MODEL. 2 SHEETS-SHEET 2.

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' UNITED STATES Patented May 5, 1903.

PATENT OFFICE.

THOMAS J. JOHNSTON, OF BROOKLYN, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMER.

SPECIFICATION forming part of Letters Patent N 0. 726,936, dated May 5, 1903.

Application filed November 1, 1902. Serial No. 129,866. (No model.)

To all whom it may concern:

Be it known that I, THOMAS J. JOHNSTON, a citizen of the United States, and a resident of Brooklyn, in the county of Kings and State of New York, have made certain new and useful Improvements in Transformers, of which the following is a specification.

In the transformers for large outputs now.

-so commonly used in distribution of elec- |o trioity by alternating currents the temperature attained by the apparatus, due-to its electric and magnetic resistance, is the limiting factor, and many arrangements have been made for conveying away the heat in- [5 cident to their operation. Air-blast transformers, so called, and oil-cooled apparatus are both in common use, while in some cases auxiliary means have been provided for cooling the oil or air. It is to the latter class of apparatus that the present invention appertains. It consists in providing in the casing, which surrounds the working parts of the apparatus and serves as a containing vessel for them and for the oil With which the larger sizes are commonly filled, channels through which a cooling medium maybe circulated. This casing is commonly constructed of cast-iron. The most convenient way in which it has occurred to-me to em- 50 body my invention is by shaping pipe of suitable size into a coil or form approximating in contour to the casing and then casting the latter around the pipe, which is placed in position in the mold, thus forming an integral construction of sufficient strength provided with interior channels, which may be of proper smoothness to permit a ready circulation of the cooling medium which may be selected.

The invention is especially adapted to the large oil-filled transformers to which I have referred and in conjunction with which it is desirable to use a cooling fluid, such as water, circulating in the casing, with suitable means to insure the circulation. Since the currents of convectionare ordinarily relied upon to insure the circulation of the oil and as the hot oil collect-s at the top, it is ordinarily best to have the water enter the pipe at the bottom of the casing, as by this means there is always a considerable difference of paratus would thus be impaired.

temperature between the water and the oil near which it is flowing in the casing, whereas if the water entered where the oil was hottest as it circulated downward it would eventually come to a part of the apparatus where the oil was but little, if any, warmer than the water, and the efficiency of the ap The distribution ofthe pipe or channels in the cas- 6o ing may be chosen as the engineer desires; but I prefer to closely approximate the coils near the top, leaving them more open toward the bottom of the casing.

The accompanying drawings show embodiments of my invention in a Well-known form of transformer.

Figures 1, 2, and 3 are sectional views of various arrangements, and Fig. 4 is a diagram showing the pipe connections of the ap- 7o paratus.

In Fig. 1 I have shown an arrangement in which channels are cast in the iron of the apparatus, which may be effected in any way well known in the art. A is the casing, and B B are the channels. The core of the transformer is shown at C; but I have not deemed it necessary to illustrate the coils, as they constitute no part of the invention. The oil is indicated at D and the cooling fluid at E.

InFig. 2 I have shown a similar section of the transformer, with reference-letters indicating the same parts; but here the channels B are replaced by a pipe F, which in the case illustrated forms a continuous channel through the iron of the casing. The pipe is here arrangedhorizontally, and the coils are crowded closer together at the top of the casing, as referred to in the statement of invention.

In Fig. 3 I show a similar section; but in this case the arrangement of the pipe is vertical. This is not so good as the form shown in Fig.2; but the difference is not important.

In Fig. 4E1 have shown in diagram the trans- 95 former with its system of circulating-pipes and a pump G with a tank H. As indicated by arrows, the circulation is from'bottom to top of the transformer for the purpose already indicated.

It is of course within the power of the engineer to change the embodiment of the invention in many particulars. There may be, for example, more than one of the channels; but I have not deemed it necessary to illus- (rate this, as it is a mere duplication.

Having thus described myinvention, what I claim, and wish to protect by Letters Patent of the United States, is-

1. In a transformer, a casing provided with one or more channels for the circulation of a cooling medium.

2. In a transformer, a casing of cast metal with channels formed of pipe embedded in the metal.

3. The combination with a transformer, of a casing provided with one or more channels and means for circulating therein a cooling medium.

4. The combination with a transformerconteas-3e taining oil, of a casing having one or more channels for the circulation of a cooling fluid.

5. A combination with a transformer, of a casing containing one or more horizontal channels; the channels being closer together at or near the top of the transformer.

6. The combination with a transformer, of a casing provided with channels and means for circulating acooling medium through the channels from the bottom to the top.

In testimony whereof I hereunto set my name, in the presence of two witnesses, this 24th day of October, 1902.

THOMAS J. JOHNSTON.

Witnesses:

ALBERT G. DAVIS, ALEXANDER D. LUNT. 

